The invention relates to a method and an apparatus for the filtration of liquids and gases.
More particularly, the invention relates to the filtration of liquids and gases using a filtering apparatus having a brush-like or mop-like filter element.
In all known filtering methods and apparatus, it is necessary to clean the filter element after a certain amount of use. The reason resides in that the filtering medium, which is the part of the filter element that removes suspended matter, e.g., particles, from the fluids undergoing filtration, becomes loaded with the suspended matter and no longer serves its function. The cleaning of the filter element may, for example, be accomplished by backwashing the filter element with a liquid or a gas, by scraping or rinsing the filter element or by subjecting the filter element to centrifugation. After the filter element has been cleaned, it is usually necessary to provide a fresh layer of filter material on the filter element. This may involve replacement of the entire filtering medium or deposition of a filter aid on the filter element. A disadvantage of this procedure resides in that the renewal of the layer of filter material consumes large amounts of material and is expensive.
Procedures for regenerating or cleaning the filter aids used in conjunction with filter elements are also known. These procedures may be carried out subsequent to wet or dry filtration and involve freeing the filter aid from the mud or dirt which is admixed therewith by sieving, washing or decantation. Thereafter, the filter aid may be re-used. These procedures are again troublesome as well as expensive.
The German Gebrauchsmuster 1,963,821 discloses a filtering apparatus having a removable filter element which is in the form of a brush. The filter element is provided with helical rows of bristles which become increasingly densely packed with decreasing distance from the outlet of the filtering apparatus. The bristles of the filter element serve as a filtering medium. In order to regenerate the filter element, it is removed from its housing and cleaned. This regeneration procedure is again expensive and also consumes large amounts of material.